Slant/Fin Galaxy GXHA
Model Number: GXHA
A low-profile cast-iron gas steam boiler, GXHA-100 to GXHA-200, about 81% AFUE, chimney vented, with a 10-year steam warranty.
Technical Specifications
Source: manufacturer spec sheet · checked Sep 27, 2026
Prices depend on sizing, venting and piping in your home, so we quote every installation.
Sizing: the right size comes from a room-by-room heat-loss calculation, not the size of the old boiler or a rule of thumb. Oversized boilers short-cycle and waste fuel; steam systems are sized to the connected radiation instead. See how we approach boiler installation.
Home-Specific Operating Cost Review
No guaranteed annual savings or payback period
Historical Use
Fuel consumption and weather
Current Rates
Utility and delivered-fuel prices
System Design
Load, piping, controls, and temperatures
Full Specifications
- Model Number
- GXHA
- Efficiency (AFUE)
- 81.3%
- Boiler Type
- Steam Boiler
- Fuel
- natural gas/propane
- Venting
- natural draft (integral draft diverter)
- BTU Input Range
- 100k - 200k BTU
- Domestic Hot Water
- optional tankless coil
- In Production
- Yes
- Heat Exchanger Warranty
- 10-year limited (steam)
Specifications sourced from the manufacturer spec sheet, checked Sep 27, 2026.
Ideal For
Older homes with steam heat and low basement ceilings that need a chimney-vented replacement.
Expert Review: Slant/Fin Galaxy GXHA
The Slant/Fin Galaxy GXHA is a low-profile cast-iron gas steam boiler with an integral draft diverter. It is not a condensing boiler. Slant/Fin's ratings chart lists four sizes, the GXHA-100, 120, 160 and 200, covering 100,000 to 200,000 BTU/hr of input at 81.0 to 81.3% AFUE. It burns natural gas or propane, vents through a chimney and can take an optional tankless coil for domestic hot water. Galaxy steam models carry a 10-year limited heat-exchanger warranty.
Key Features & Technology
Cast-iron sectional heat exchanger
Low-profile steam design
Integral draft diverter
GXHA-100 to GXHA-200 sizes
Optional tankless coil
Natural gas or propane
Advantages
- Low profile fits tight basements
- Proven cast-iron construction
- Optional tankless coil for hot water
Considerations
- About 81% AFUE, not condensing
- Needs a lined chimney
- Steam warranty is 10 years
Sizing & Installation Notes
Steam boilers like the Galaxy GXHA are sized to the connected radiation — we measure every radiator's EDR rating and match the boiler's steam output to that total, plus piping pickup allowance. Square footage rules of thumb don't apply to steam.
Every Slant/Fin installation starts with a free in-home assessment covering the heat-loss calculation, venting and chimney condition, and gas or oil supply sizing. Learn more about our boiler installation process and steam boiler installation, or see current rebate and incentive programs that may apply.
Warranty & Protection
Parts Warranty
See spec sheet
Heat Exchanger
10-year limited (steam)
Our Guarantee
100% Satisfaction
All Slant/Fin boiler installations by Home+ Air & Heat include our 1-year workmanship warranty, covering labor and any installation-related issues.
Compare the Slant/Fin Lineup
| Model | Efficiency | BTU Range | Fuel | Heat Exchanger Warranty |
|---|---|---|---|---|
| Galaxy GXHA (this model) | 81.3% AFUE | 100k - 200k BTU | natural gas/propane | 10-year limited (steam) |
| Lynx | 95% AFUE | 25k - 150k BTU | natural gas/propane | 15 years |
| Sentinel | 82.3% AFUE | 70k - 210k BTU | natural gas/propane | lifetime limited |
| Intrepid Direct Vent | 87% AFUE | 103k - 132k BTU | #2 fuel oil | see Slant/Fin cast-iron boiler warranty |
| Bobcat B-120A/200A | 93% AFUE | 30k - 200k BTU | natural gas/propane | 12-year residential (5-yr full + 7-yr prorated) |
| CHS-85-399 | 95% AFUE | 17k - 399k BTU | natural gas/propane | 15-year residential limited (includes 5-year Protection Plan) |
| Galaxy GX/GXH/GXHA | 81.3% AFUE | 100k - 300k BTU | natural gas/propane | 10-year limited (steam) |
| Intrepid Hot Water | 86% AFUE | 89k - 358k BTU | #2 fuel oil | see Slant/Fin cast-iron boiler warranty |
| Intrepid (steam) | 86% AFUE | 105k - 469k BTU | #2 fuel oil | see Slant/Fin cast-iron boiler warranty |
| Intrepid (water) | 86% AFUE | 105k - 245k BTU | #2 fuel oil | see Slant/Fin cast-iron boiler warranty |
| Victory VSPH | 86.1% AFUE | 60k - 180k BTU | natural gas/propane | lifetime limited |
| Jaguar J-390C | 90.2% AFUE | 390k - 390k BTU | natural gas | — |
| Monitron | Not verified | 27k - 137k BTU | electric | — |
| Sentry S-34-210 | 84.4% AFUE | 34k - 210k BTU | natural gas/propane | lifetime limited (verify on certificate) |
| VSL-160C | 92% AFUE | 30k - 160k BTU | natural gas/propane | 15-year residential limited (VSL warranty) |
| Galaxy GG | 84% AFUE | 95k - 399k BTU | natural gas/propane | lifetime limited (hot water models) |
| VSL II | 92% AFUE | 90k - 250k BTU | natural gas/propane | 15-year residential limited (VSL warranty) |
| Lynx LX-85-150 | 95% AFUE | 25k - 150k BTU | natural gas/propane | 15-year residential limited (includes 5-year Protection Plan) |
See the full Slant/Fin brand page for lineup context, or browse the Best Steam Boilers 2027 guide to compare across brands.
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